DEVICES AND APPLIANCES. 273 



capstan. The plow or mole was sefc in at the pond and 

 run over the hill, the water following In-hind. Stran^v 

 as it may seem all of the water was taken out of the 

 pond. The drains were practically siphons, and when 

 completed were full of water, so that they acted as 

 siphons as long as the water supply lasted. When omv 

 empty their action ceased and could not be brought about 

 again unless the drains were filled with water, which of 

 course could not be done. These examples and others 

 which have come under our notice, show that under cer- 

 tain conditions tile drains can be made to operate very 

 much as tight pipes. We observe, however, that for all- 

 round drainage purposes tiles must operate freely, with- 

 out being forced, except for flushing in flood times, when 

 we may expect to see tile lines crowded beyond their 

 capacity for good drainage purposes. 



The Siphon Elevator. This contrivance is com- 

 posed of two pipes of unequal diameter, a receiver and a 

 regulator. In the interior of the receiver a clack valve 

 is placed, so as to cut off, intermittingly, the flow of 

 water into the regulator, and above it is a puppet valve 

 maintained in its place by a spiral spring. A lever car- 

 rying a counterweight is attached rigidly to the axis of 

 the clack valve, causing it to open. The regulator is 

 formed of a cast-iron drum, having thin corrugated 

 heads. At the bottom of the suction pipe is a check 

 valve, which allows the ingress of the water but prevents 

 the escape. At or near the bottom of the discharge pipe 

 is a stopcock. The siphon elevator is filled with water 

 the first time through the orifice, which is then closed by 

 a screw cap. 



Its operation is as follows : By opening the stopcock 

 in the pipe, the water in the siphon is submitted to at- 

 mospheric pressure, with which it seeks equilibrium. 

 Therefore, as it falls in one pipe it ascends in the other 

 pipe and penetrates into the receiver, where, meeting the 

 18 



